YEREVAN -- A senior Armenian official has said the government will probably delay by several years the decommissioning of a Soviet-era nuclear power station, RFE/RL's Armenian Service reports.

The plant, located some 30 kilometers west of Yerevan at Metsamor, was built in the 1970s but closed following a devastating earthquake in 1988. One of its two reactors was reactivated in 1995.

Since then, Yerevan has been under pressure from the United States and the European Union to close the plant permanently.

Armenian officials have insisted for years that the reactor, which provides about 40 percent of Armenia's electricity, is safe enough to continue operating at least until 2016.

The government announced in 2005 that it was already making preparations for the launch of the decommissioning process. It said the process would be carried out in parallel with construction of a new reactor meeting modern safety standards.

Energy Minister Armen Movsisian said last year that work on the facility would start by the beginning of 2011.

But Ashot Martirosian, the head of the State Committee on Nuclear Safety, told RFE/RL that "the construction of a new [power-generating] unit will probably start in 2012 and, assuming that it will take six years, will end in 2018."

He called the plan to start construction of a new reactor next year "unrealistic."

Martirosian said the authorities were "thinking about keeping the functioning unit [at Metsamor] operational for two or three or four more years," and would seek clearance to do so from the International Atomic Energy Agency (IAEA), the UN's Vienna-based nuclear watchdog.

He told RFE/RL that the authorities were ready to take additional safety measures at the plant in order to keep it open longer.

Metsamor's safety has been boosted with tens of millions of dollars of assistance provided by the United States and the EU, and it regularly undergoes repairs and maintenance.

But its VVER 440-V230 light-water reactor is considered by the EU to be one of the "oldest and least reliable" of 66 such facilities built in the former Soviet Union and Eastern Europe.

It is due to be replaced by a new generation of Russian-made VVER reactors, which Armenian officials say meet the IAEA's safety requirements. Armenia and Russia have recently set up a joint venture tasked with building the new reactor.

The Armenian government has also approved the overall design and main technical parameters of the facility. With a projected capacity of over 1,000 megawatts, it would be more than twice as powerful as the current Metsamor reactor and leave Armenia with an electricity surplus.

Martirosian said a team of IAEA experts inspected the designated site of the new reactor last week. "The mission's preliminary report says they still need answers to some questions and a more detailed examination needs to be conducted," he said. "But that is not a big deal."

The key problem for the government is how to finance the project. A U.S.-funded feasibility study conducted in 2008 estimated the total cost at $5 billion, twice Armenia's entire state budget for this year.